feat: Single drive XL implementation (#14970)

Main motivation is move towards a common backend format
for all different types of modes in MinIO, allowing for
a simpler code and predictable behavior across all features.

This PR also brings features such as versioning, replication,
transitioning to single drive setups.

cmd/bucket-targets.go

@@ -120,9 +120,6 @@ func (sys *BucketTargetSys) SetTarget(ctx context.Context, bucket string, tgt *m
 		return BucketRemoteConnectionErr{Bucket: tgt.TargetBucket, Err: err}
 	}
 	if tgt.Type == madmin.ReplicationService {
-		if !globalIsErasure {
-			return NotImplemented{Message: "Replication is not implemented in " + getMinioMode()}
-		}
 		if !globalBucketVersioningSys.Enabled(bucket) {
 			return BucketReplicationSourceNotVersioned{Bucket: bucket}
 		}
@@ -184,9 +181,6 @@ func (sys *BucketTargetSys) RemoveTarget(ctx context.Context, bucket, arnStr str
 	if globalIsGateway {
 		return nil
 	}
-	if !globalIsErasure {
-		return NotImplemented{Message: "Replication is not implemented in " + getMinioMode()}
-	}
 
 	if arnStr == "" {
 		return BucketRemoteArnInvalid{Bucket: bucket}